Bug 653135

Summary:	RFE: vlock should be able to lock terminals when execute from a daemon
Product:	Red Hat Enterprise Linux 6	Reporter:	Gal Hammer <ghammer>
Component:	vlock	Assignee:	Karel Zak <kzak>
Status:	CLOSED NOTABUG	QA Contact:	BaseOS QE - Apps <qe-baseos-apps>
Severity:	medium	Docs Contact:
Priority:	low
Version:	6.0	CC:	iheim, tmraz
Target Milestone:	rc	Keywords:	FutureFeature
Target Release:	---	Flags:	ghammer: needinfo+
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Enhancement
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2010-11-15 13:08:58 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	565939, 641886

Description Gal Hammer 2010-11-14 16:20:23 UTC

In RHEV-M, when a user, using a SPICE client to connect to a guest, close the connection, the vdsm tells the guest agent to lock the machine. The RHEV-agent daemon tries to lock the machine by calling "/usr/bin/vlock -a" but the execution always fails.

It is possible to lock the virtual terminals this way?

Comment 2 Karel Zak 2010-11-15 11:06:59 UTC

(In reply to comment #0)
> In RHEV-M, when a user, using a SPICE client to connect to a guest, close the
> connection, the vdsm tells the guest agent to lock the machine. The RHEV-agent
> daemon tries to lock the machine by calling "/usr/bin/vlock -a" but the
> execution always fails.

What does it mean "execution fails"? (do you have any error message?)

> It is possible to lock the virtual terminals this way?

I think that "vlock -a"  makes sense on standard consoles (tty0 ... tty16) on machines where all consoles are accessible from the same physical place.

The "vlock -a" does not lock all consoles, it locks the *current console* and  controls switching between consoles (e.g. Alt-Fn keys). So after "vlock -a" you cannot use or leave the current console without a valid password. That's all.

Comment 3 Gal Hammer 2010-11-15 12:33:56 UTC

(In reply to comment #2)

> What does it mean "execution fails"? (do you have any error message?)

I'm using Python's subprocess.call. The function returns 1 when I execute vlock.

> The "vlock -a" does not lock all consoles, it locks the *current console* and 

I'm okay with this behavior. The problem is that I'm executing vlock as a daemon which doesn't have a *current console* to lock.

Comment 4 Karel Zak 2010-11-15 13:08:58 UTC

vlock opens /dev/tty, this special device is associated with the current process terminal. 

Yes, it probably does not makes sense to call vlock -a from any daemon if the daemon is outside the current session (terminal).

I have no clue how to fix your problem. Try to ask at tech-list.

Comment 5 Tomas Mraz 2010-11-15 13:38:05 UTC

IMO the most appropriate way for locking the consoles on a guest is to reserve one of the consoles for the vlock and in case of timeout switch into this console and run vlock -a in it.

Comment 6 Gal Hammer 2010-11-15 13:57:19 UTC

(In reply to comment #5)
> IMO the most appropriate way for locking the consoles on a guest is to reserve
> one of the consoles for the vlock and in case of timeout switch into this
> console and run vlock -a in it.

Thanks. I'll try it.